Energy is the vital force driving the world's economies. Energy is needed for transporting goods and services, manufacturing and business. Energy is needed in the home for electricity, cooking, heating and for powering vehicles. The search for alternative sources of energy is an ongoing process, but there are numerous sources of energy.


Oil is a traditional source of energy, derived from the remains of creatures that died many years ago. It is referred to as a nonrenewable source of energy because it takes so long to form.  According to Chevron, more than a trillion barrels of oil have been produced worldwide. Fears over dwindling reserves have spurred the quest for alternative, renewable sources of energy. Oil is used mainly to produce transportation fuels and the demand for oil is projected to grow as the need for it grows.


Hydropower is derived from water. It powers machinery and generates electricity. Hydropower  works by tapping into the water cycle. The term "water cycle" is used to describe the constant motion of water on Earth. Water is always moving on the planet by forming clouds, evaporating from oceans and lakes and falling as rain or snow. This cycle is driven by the sun and can be tapped into to for mechanical tasks like grinding grain or for electricity production, known as hydroelectric power. Hydropower is a renewable energy source because the water cycle is a recharging system.


Geothermal energy is created by the heat of the earth. It is considered renewable and clean energy because it does not produce any greenhouse gases. Geothermal energy also has significant environmental advantages. There are only a few places on earth that have the special conditions needed to generate geothermal energy. These places are located where there are deep fractures in the Earth's crust to allow molten rock to surge close enough to the surface to heat underground water.


Solar energy is derived from the sun. The sun's energy is tapped by converting sunlight into other forms of energy, like electricity and heat. This is also a renewable source and reduces the generation of greenhouse gases by decreasing the need for reliance on fossil fuels.